Coordinate and height accuracy

In New Zealand the accuracy of coordinates and heights is classified using a system of orders. These indicate the expected accuracy of specific components so users can assess the reliability of their geospatial data.

The accuracy of a coordinate or height can be measured in different ways. Toitū Te Whenua uses orders to determine coordinates which meet both a network and local accuracy standard:

  • Network accuracy represents the absolute uncertainty of a coordinate in relation to a datum. Network accuracy is categorised by tier.
  • Local accuracy represents the uncertainty of a coordinate in relation to other nearby coordinates. Local accuracy is categorised by class.

In general, the lower the order number the more accurate the coordinate is, with 0 the most accurate and 12 the least accurate. Three order classifications are used in New Zealand:

The current order framework has been in place since 2010. 

Read more about past coordinate and height orders

New Zealand Geodetic Datum 2000 (NZGD2000), Ross Sea Region Geodetic Datum 2000 (RSRGD2000) and New Zealand Vertical Datum 2016 (NZVD2016) order have been determined using statistical testing, in the National Geodetic Adjustment.

The National Geodetic Adjustment

Historic coordinates (such a New Zealand Geodetic Datum 1949 (NZGD1949) and local vertical datum were determined based on observational accuracy.

New Zealand Geodetic Datum 1949 

Local mean sea level datums

Historic coordinate and height orders

Last updated